Cool View of Science at Meeting on Warming

Several hundred people sat in a fifth-floor ballroom at the Marriott Marquis Hotel in Times Square on Monday eating pasta and trying hard to prove that they had unraveled the established science showing that humans are warming the world in potentially disruptive ways.

One challenge they faced was that even within their own ranks, the group — among them government and university scientists, antiregulatory campaigners and Congressional staff members — displayed a dizzying range of ideas on what was, or was not, influencing climate.

On Sunday night, the dinner speaker was Patrick J. Michaels, a climatologist with a paid position at the antiregulatory Cato Institute who says humans are warming the climate — he projects a three-degree Fahrenheit warming by 2100 — but disputes the value of cutting emissions of heat-trapping gases.

At lunch on Monday, the message from S. Fred Singer, a physicist who runs a group challenging climate orthodoxy, was that climate change was mainly driven by vagaries in the sun.

The two-day gathering, which concludes Tuesday, was organized by the Heartland Institute, a Chicago group whose antiregulatory philosophy has long been embraced by, and financially supported by, various industries and conservative donors.

Riley E. Dunlap, a sociologist at Oklahoma State University who has studied the influence of conservative policy institutes, said in an e-mail message that such events were designed to foster the impression of “little Davids battling the Goliath of the environmental establishment.”

But Dr. Dunlap said such activities were well financed and, “When you have the full support of some of the wealthiest and most powerful political actors in the nation, you can hardly be considered to be underdogs.”

The main targets at the meeting were former Vice President Al Gore, who has portrayed global warming as a “planetary emergency,” and the Intergovernmental Panel on Climate Change, which has issued four sets of reports assessing the human impact on climate over 20 years.

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The latest reports, published last year and embraced by all major nations and scientific academies, concluded that most warming since 1950 has been caused by humans and that centuries of rising temperatures and seas and ecological disruption lay ahead if emissions of heat-trapping gases like carbon dioxide were not curbed.

At the Heartland meeting, presenters critiqued computer simulations of global climate and the quality of temperature records. Others focused on the societal and economic impact of both climate change and proposed responses, including limits on carbon dioxide. Some speakers focused on past warm periods in which civilization flourished, and cold periods in which people struggled against famine.

A centerpiece of the meeting was a short report by 24 authors, led by Dr. Singer, provocatively described as the “Nongovernmental International Panel on Climate Change.” Its main conclusion was this: “Our findings, if sustained, point to natural causes and a moderate warming trend with beneficial effects for humanity and wildlife.”

Participants repeatedly attacked the idea that there was a consensus on the danger of human influence on climate. Some tried to convey the impression that their view represented an emerging and opposite consensus that humans were not warming the world — or that if they were, it was not a problem.

In the hallway outside the meeting rooms, Kert Davies, a campaigner from Greenpeace, sought out reporters.

“This is the largest convergence of the lost tribe of skeptics ever seen on the face of the earth,” Mr. Davies said, pointing to knots of participants. “How does this message of theirs stack up against that of Governor Schwarzenegger, John McCain, G. E., Wal-Mart, and everyone else who’s getting on board pushing for change? I’m the skunk at the garden party.”

The meeting was largely framed around science, but after the luncheon, when an organizer made an announcement asking all of the scientists in the large hall to move to the front for a group picture, 19 men did so.

A version of this article appears in print on , on Page A20 of the New York edition with the headline: Cool View Of Science At Meeting On Warming. Order Reprints|Today's Paper|Subscribe